Hydraulic thrust bearing



Feb. 28, 1961 DOUGLAS 2,972,962

HYDRAULIC THRUST BEARING Filed July 16, 1956 9 Sheets-Sheet 1 INVENTORJAMES K. DOUGLAS ATTORN Feb. 28, 1961 J, DOUGLAS HYDRAULIC THRUSTBEARING Filed July 16, 1956 9 Sheets-Sheet 2 INVENTOR JAMES K. DOUGLAS w0. m v 7* \E M m. Q $4? W v imw \mm vAIOm 5 Am o? ||I.| IIII ll mm T Nmm l Illlllll 5 .r m M GIN. a a mm. mm 3 m. v 6 mm ATTORNEY Feb. 28,1961 J. K. DOUGLAS HYDRAULIC THRUST BEARING 9 Sheets-Sheet 3 Filed July16, 1956 INVENTOR JAMES K. DOUGLAS BY ATTORNEY Feb. 28, 1961 J DOUGLAS2,972,962

HYDRAULIOTHRUST BEARING Filed July 16, 1956 9 Sheets-Sheet 4 INVENTORJAMES K. DOUGLAS ATTORNEY Feb. 28, 1961 DOUGLAS 2,972,962

HYDRAULIC THRUST BEARING Filed July 16, 1956 9 SheetsSheet 5 FIG.7

INVENQTOR JAMES K. DOUGLAS BYWW ATTORNEY Feb. 28, 1961 DO HYDRAULICTHRUST BEARING Fe 1961 J. K. DOUGLAS HYDRAULIC THRUST BEARING 9Sheets-Sheet 7 Filed July 16, 1956 INVENTOR JAMES K. DOUGLAS AITORNEYFeb. 28, 1961 J. K. DOUGLAS 2,972,962

HYDRAULIC THRUST BEARING Filed July 16, 1956 9 Sheets-Sheet 8 FIG. I5

INVENTOR JAMES K. DOUGLAS ATTORNEY Feb. 28, 1961 J K. DOUGLAS HYDRAULICTHRUST BEARING Filed July 16, 1956 9 Sheets-Sheet 9 INVENTOR JAMES K.DOUGLAS ATTORNEY and/or of thesurfcae in contact therewith. I

United States PatentO This invention relates to hydraulic thrustbearings of. the type employed totransmit thrust from one to the otherof two relatively rotatable members. Thrust bearingsconstructedaccording to'the invention are particularly adapted for usein hydrodynamic machines, and the invention will be explained as beingused for that purpose but it is not limited to such use.

In an axial type hydrodynamic machine, which may be either a pump or amotor, the piston thrust is transmitted through a swash plate member toa reaction memher one of which is rotatable relatively to the other.Heretofore, some hydrodynamic machines have had an annular bearing platefitted between the two members and provided in one face thereof witha'plurality of pressure pocketswhich, during relative rotationof thetwoimemberu, registers successively with a plurality of holes whichextendthrough the swash plate member and communicatewith the cylindersso that the pockets are supplied with'liquid from the cylinders. Liquidwill seep from the pockets and'form ,alubricating film between themating faces of the'bearing plate on the swash plate member;

"l hepressure in the pockets on the pressure side of the machine is thesame as the pressure in thelcylinders on the'same' side of' the machineand it extends into the lubrieating. film. Theliquid in the pockets actsas a liquid bearing and the face of the bearing plate around and betweenthe pockets is a bearing area which normally is coveredfby' thelubricating film. The pressure in the film at the edges'of the pocketsis the same asflthe pressu're'in the pockets and it decreases to zero atthe edges of the bearing area. The pockets and the, bearing area mustbeso proportioned that the forces exerted, by the liquid'in the' pocketsand in'the lubricating 'film' is less A valve ports' one of which isalliigh'pressureport' and the transmitted through other ofwhich is a lowpressure port. 'During operation of the machine, 'liquid. seepsgfrom thevalve ports and forms a lubricating filnibetween the face ofthe valveandthe end of the, cylinder barrel. Pressure extends from thehighpressure-valveiport into that film and ordinarily enables,it,toprevenqmetal to-- metal contact between-the valve and-. thecylinder ,bare rel. But: when the machine operates. atIvery-high -.pressures, portions of he film are sometimessqueez'ed out and abrasion ofthe'valve and/or thecylinder barrel occurs 'The present invention has -as,an,object to providea hydraulic thr'ust'beari'ng: in whichalubricating film of, liquid is pesitively maintained between, tworelatively rotating surfaces, regardless of the, magnitude of the;

the bearing or variations in the viscosity of'the liquid in the film.

Anotherobje'ct isv to provide hydraulic thrust bearing means which ismore efiicientthan any such means heretofore employed between the swashplate member and I the reaction member of a hydrodynamic machine.

Another object is to provide hydraulic thrust bearing. means which ismore efiicient than any suchmeans heretofore employed between thestationaryyalve and the rotatable member of a hydrodynamic,'machine.These and other objects and advantageswill appear.

' i from the following description of the embodiinentsof the thanthepiston thrust as otherwise they "wouldjcaus'euv separation of the matingsurfaces and a"resultaint large loss of, liquid. 1

large part of the piston"thr'ustis: transmitted th'iough-the' liquid" inthe pockets, and the remainder thereof'is transmitted through the'bearing' area." But when-a"machineo f large capacity is'operatingundefia very high pressure, the pistonthrust is enormous,deflection of parts and; distortion of metal occurs, and portions" ofthe lubricating filni are squeezed out and-permit metalf to rnetal'contact between the relatively rotating 'surfaces," therebyc'au'singabrasion of the parts of'the bearing area 'In ahYdrcS-dyn'amic machinehaving its pistons and cylinders arrange'deither radially or axially in-a rotatthe cylinder barrel has two arcuate 'ports formed therein,

in the plane indicated .,by the nae-1' a dcommunicating with passageswhich may bei con- 'nectedto'an'external circuit, and eachcylindercommunicatesfwith a port which extendsthrough theend of the cylinderbarrel'and registers during rotation of'the; cylindei-btirr'elfirst withone and then the other'of the two I in Fig.- 6, .the plane of of Fig.510 but drawn to thesame scale'as Fig.' 2.

invention illustrated in the accompanying 'j drawings in. which'theviewsare'as follows: 3 Fig. 1 is a vertical longitudinal section througha by drodynamic machine having embodiments of. the in-. ventionincorporated therein, certain parts of the machine being broken away andomitted from thefdrawingf Fig. 2 is a fragmentary sectional view takenthrough? the center of the piston and piston rod assembly shown in Fig.1 but'drawn toamuch larger scale. t Fig. 3 is an end view ofthe"cylinder.barreljtheview being taken on theline 3-3 of Fig.1. Fig;4'isa,.face view" of the valve which controls'the flow of liquid to andfrom the cylinders, the viewheing taken on the line 44 of Fig.1} butdrawn to a larger scale. Fig. 5 is a section taken through the valve "ofFig. :4. and thrdughadjacent partsand 'portionspf other'fad jacentparts, the plane of the'view being indicated bythe v line 5-"5 'of Fig.4. v i i Fig'. 6 is a 'view of the face of" awear plate which eh? gagesthe end of the'cylinderbarrel shown in Figl f' 3, the view being' drawnto the' samescale as FigiS and taken' ontheline 6-.-'-6 thereof. e iFig. 7 is a view of the other, face of the plate sho the view; beingindicated by the line 7-f-75of Fig.5. a v Fig. 8 is aview of the face-ofa thrusnbearing plate. which engagesthe face of the valveshown='in-:Fig. ;4,

vFig. 9 is a .view of the ,olther faceof theiplate shownin Fig. 8, "th'eview being takenon the line yiof Fig. Fig. 10'is afv'iew of one face ofa t hrust bearingplate in whichthe invention is embodied, the view beingta'ke 0 6r rig. fzhtit drawnto a'smallerscale'than Fig; 2. I Q I Fig. 11is 'a' view of theother'faceofthe plate shown in Fig. 10, the plane'ofthe'view beirigindicated bytlie f line'11'11'of'Fig.2; Fig. '12'-is' asectional view taken oii'the line Fig. 13 is a sectionaljviewstaken onthe1' line' 13-i3 of Fig. .10 but drawn to the same scale .as 'Fig. 2-."Fig.. 1 is a sectionalview,taken on ithexa-rcuatesline a Fig- 17 is avi'ew which corresponds, to'Fig'; 4 jb utf ashy rneans ,of two bearingsandf6. Shaft 51 extends pl t ii lfi m su mtia vapart y n er barrel 17 Ia spherical qheadi20-whichforms a partiof a' ball' -and T lineawn-crate: "I

showsa modification arrgmwgap i I a t 'Fig. l8 is aview takenthroughfthe valve shjownj in 1 Fig. 17 and 't-hrdiilgh'portions ofa'djacent parts, the plane ofi the view being 'indic'atedby theline IS-" 1 8 of Fig. 17,

For the purpose-of ust'r'ationQftheinventi n has 1 showninoorporat'edilin' a hydrodynamic fmachine is substantially the same-2:5 fthe hydrodynamic machine I 7 fully i llustrated and describedinjapplic'ation of Adolph R. Grad filed Octoher*26,1 1253'; and issuedas U.S.

7 Patent 2'-,804,8 28,"except that it"ha's' the present inventionincorporated therein and fis provided with piston and piston rodassemhlies ot thevtype shownl in application Serial No. 545,242,'filed;Novemberi'lgwsinow Patent No. 2,850,986. 'ThereforeQorjlY so muchof the machine 7 has been illustrated a s isineee'ssary for anexplanation of the invention.

Such machinesjwill function as pumps when driven mechanically and willfunction as motors when supplied with motive liquid. Since the functionof a pump is'sub stantially opposite to theffuriction of a moton'the'invention will be explained as beingincorporated in a pump in order tosimplifythejdeseription butit'is to be tinderstood that the invention isequally applicable" to motors and that referring to the 'mat ine asapurnp inno way v limits theinvention to purnps. V

A k a d. n glit pump ie rits h ni m ring 1 whichlisclosed tat its leftend distributorjbloclc sgthicughfwmch liquid flows to and fro'tnanexterhal circiiitf"Block 3 has': a drive-shaft 4 extendingtherethrough'yand rotatably' supported therein outward! beyond block, 3;fonconne'ction to source or; power and its inner-i portioh supports?cylinder;har rel, 7

which hasla borehfextendiug therethroughgto; receive shaft 4.,Thejpumplias 1beenmade vvith.its :drive shaft extending through thelft'end'of the casingand supi p edl rrives afi a in s w s o espo dwhee ar 5/ and 6 d e a ne by n h a ss o s o d n toie nd he ads :aiid ,3Cylinder barrel .7 is, fixed a5; 1 a

[ rotation with shaft 4, as by means etakey 9, and;it

e -sh e sh w p ovided-9n itsi g t d-wi We and it is fixed for rotationtherewithqas by meanswjof:

ifiylinderzbarrel ll-has aplurality of cylinders 14 formed 1 therein andequally spaced in a circular row:Qwhichil-is concentric with-shaft 4.Each cylinder' 14 has an eloni gated port ISjeXtending from its innerendthroughthe 60 .7 Aflpis'tion l6 'is' j fitted in each cylinder14jjandrf provided right end of cylinder-barrel 7 and through ,wearplate'lili witfhlalf piston] 17 by rrie'ans of whichj piston v 16 is cigde ih -dus i ia artjis;

The'pistona nd pistonj-rod a sse rnblre re all alilre a d,

and engaged'by a'isvphelical head 19 s m ne a L Fig; Sfeach includes acylinder 51 which is formcdrin tag-piston rod 1@7 the other endof-rwhichisrrforrned into 70 soeket -,joint21.-.as.will presently he explain'ed.Head 19 aerape a 7" withcylinder Barrel 7 by pins ss;

'holes'flli reareing Shaw a p 4, and valve pqttglo s forces to betransmitted therethrough and thereby enable a piston 16 to create veryhigh pressures in cylinder 14.

Y a bore 26 extending firom -s'eat zkthrough headY ZO.

1 Head,19'is 'held' 'in contact 'vvi'thseat" 18 by a pin 27 haYi gaa'sphgricalrhe'ad Z BztheLsnIi-"Eace. of which is comr yi-to and' irfcontact with'sea't 24. sin 27 extends through opening 25 and bore 23int-o recess 22 and has a cannelurejfi formed ;in the portion whichextends intorecess' 22. When connecting piston 16 and piston rod 17 toeach -other, head- 2 8 is urged against seat 24, head 19 is urgedagainst seat 18 and then a head 30 of suitable metal is swaged intocannelure 29 with its innerend in contactiwiththe endwall of recess 22',thereby preventing 1 any irel'ativeiaxial rrnove ntent betweenpistonfl'fi and'rbd 17 while perrriitting rod 17 to gyrate relatively topiston 16 as.v cylinder barrel 7 rotates. In order to "provideliquidvfor lubrication and holdup 7 purposes, pin 27 ha's'lextendingaxially therethrough a passage31'through which liquid can flow andpressure can extend rfromlcylinder lflinto the passage 26 in rod 17. Inorderftoprovide Iiquidfor control purposes shaft'l is connected byashaft 32 to a 'gear pump-33 (Fig. l)' 'w hich i's c'arri'ed by end head2 but. will not be described heeauselit doesndt forn1 anyip'art ofthepresent j inventionrf The flow of: iquidlintoand out of the severalcylinders 14 is controlled by a hat valve which encircles shaft 4Jandisre'strained fronf rotation by pins 36. The flat engage'the'flat'en'd ofithe cylinderharrel as indicated iriFig. l8fbfutit has beencustomary for a long timeto providewear; plates betweenllie cylinderbarrel andthe valve in pumps air meme As shown, an annular he ring plate37 is mounted upon the Hat face of valve 3 and forms in efieet a partof' va1ve 35, Plate 37 is substantially in contactwithfthe wear plate 10oincylinder- .b'arrel "71 and it is supported van chp revented from arotating During ro ta'ion of c linden barrel 7; each cylinder 5 port 15'registers alternately with two varcuate. valve ports 3 39' and itllwhieh are 'found inplate fl and in valve 35. T In order-tostifienp1ate37, ithas .a plurality of struts 41, formed integral,threwith 'and joining opposite sides 7; of port v3) and a plurality 'offstrut s 42 formed integral 3 therewithand joining opposite sides ofport 40, thestruts being thinneifithan plate 37 and: spaced from bothfaces:

' hsie fgate-: a h a the ven n PQr t. therein providingyit' with centainrecesses and grooves a as will presently be explained,

Valve W emtnv it a pl ra i sh z communicates with equalnurnher. ofoblong holes Each holev43co'rnrnunica-tes with a hold-up motorn45 anele' m un s esiw h a hol m9 7 46 all of. which arearranged withi valve35. Each holdup. mot-M45 iregisters flwitha hole 475 (Fig. '5). andeachl o dr' "m t v 6 t i ta'sv t i 5 hole 48 twhkhar 'e tormedin block 3,only one hole 4:7andgnehole 4ti; "ap in ed av s/ Hole 47 nd 48 wmmu i ae 65' respectively; i with two; passages 49' and- ?50 which are oppositesides'offa hydrauliccircuit.

The ma-u wa a e n i e an sssin w i i valve 35, a tubular piston 52 whichis fitted in cylinde 39 or 40 and by the pressure in the film of liquidbetween the'face of valve 35 and the end of cylinder barrel 7. But thepressure in the high pressure valve port 39 or 40 extends into thehold-up motors 45.0r 46. in communication therewith and enables thosemotors to urge valve 35 toward cylinder barrel 7 with a forceproportional to the pressure.

Valve 35 is also provided with balancing motors. (not shown) which areintermittently energized, as shown and explained in US. Patent2,804,828, and the sum of-the forces exerted by the holdrup andbalancing motors slightly exceeds the blow-01f force so that theadjacent surfaces of cylinder barrel 7, wear plate 10, hearing plate 37,and valve 35 are firmly held in contact. f

Pistons 16 are reciprocatedw by motion transmitted thereto through aswash plate 57 (Fig. 1) to which the several pistons 16 are connected bythe piston rods 17 and the ball and socket joints 21. As shown in Fig.2, each joint 21 includes the head 20 on a rod 17'and a spherical socket58 which is closely fitted upon head 20 and is fitted within a pocket 59formed in swash plate 57.

In order that swash plate 57 may pull pistons 16 outward on suctionstrokes,.that part of socket 58 outward from its transverse centerlineis spun or swaged into contact with the surface of head 20 and aretainer'ring 60 is arranged between socket 58 and a snap ring 61arranged in a suitable groove formed in .the wall ofpocket 59. Liquidmay flow and pressure may extend from the passage 26 in rod 17 to theleft-hand face of swash. plate 57 through apassage62 formed in swashplate 57 and in socket 58'. Swash plate 57 is rotatably supported by astationary reaction member or cradle 63 having an integral central horn64 and two integral arms 65 and 66 which. are' arranged diametricallyopposite each other and arepivotally supported by two trunnions 67 arid68, respectively. Trunnion 67 is carried by the lower wall of casingland.

by a web 69 which is formed integral with casing L Trunnion 68 iscarried by the upper wall of= casing land by a web 70 which is formedintegral with casing 1; Trunnions 67 and 68 are ordinarily provided withantifriction bearings which have been omitted from the drawing in orderto simplify the view. I

The radial components of the pumping'forces'aretrans mitted through abearing 71 which is carriedby horn 64 and rotatably supports swash plate57. The axial.

components of the pumping forces may be transmitted-directly betweenswash plate 57 and cradle 63 and a trust bearing embodying the presentinvention be formed'integral therewith but preferably they aretransmitted through an annular thrust transmittingwear plate 72.an'd.

an annular thrust receiving bearing plate 73 in :which the presentinvention is embodied and which will'presently be described. As shown inFigs. 1 and 2, wearplate 72'. engages the flat left face of swash plate57 and is fixed for rotation therewith as by means of apin 74 so that itforms substantially a part thereof, and bearing plate 73 is carried bycradle 63 and is restrained fromrotation by a pin 75 so that it formssubstantially apart of cradle 63. Means comprising pins 74 and 75support the" wear plate and the bearing plate, respectively; for axialmovement relative to their respective supportin g frnem bers, asindicated in Figs. 1 and 13.

Swash plate 57 is fixed for rotation with 'cylinder' barre'l 7 by auniversal joint comprising two rings 76' a'nd 77 plate 57 diametricallyopposite each other; Ring 77 has two pins 80 extendingitherethrough inthe same radial plane as, pins 78. .Eachlpin 80 connects ring 77 to aplunger. 81 .which is" slideable .in-a bore 82 formed in cylinder barrell7. -;Rings .76. and 77 are pivotally 0on necteditoieachv other atvdiametrically opposite points spaced 90i-from pins-78 and 80. 1 i A t::The arrangement-is such that, when cylinder barrel 7 is rotated andcradle. 63 isinclined to shaft 4,--universal joint ..76.81. willrotateswash plate 57 withcylinder barrel .7. and swash plate- 57 willreciprocate pistons 16 and thereby cause the pump-to discharge liquid ina direction and at a rate dependent upon the direction and distancecradle 63 is inclined from, its neutral position. Referringnow to-Figs.-,15 and 16, wear plate 72 has a plurality-of recesses 83 formedin theface thereof which engages: bearing plate 73. and a recess 83formed inits. opposite, face in axial alignment with -each recess 83 andconnected thereto byahole 84. .Recesses 83 and 83 areiarranged. incircular'rows with each pair of re-' cesses in .the radial plane. of apumping cylinder 14.

- Each:recess 83registerswith apassage 62 (Fig. 2)-- in thezsame radialplane-so that the pressure in each} pair of -recesses83 and 83 isthesame as the pressurein'the :cylinder-14-.in: the same radial plane.-That is, the pressure in each pair of'recesses 83'and 83 will be the'sameas the pump pressure during one-half of each revolution of:cylinder barrel 7' and will be approximately zeroduringthe other halfof each revolution of cylinderbarrel.1.-;"

. 1 wPressurein recesses 83*" will cause. liquid to-seeptherefrom andform a film of liquid bjetween theadjacent faces .of plate 72 and swashplate 57 and pressure will-extend into that filmfrom the; recessescontaining pressure. Inaordertto. limit the area ofnthe film into whichpressure. can; extend, two annular. limit grooves 85..and 86 are-formedin plate .72 upon opposite sides of:

85eand 86 ,:respectively.': a 1 ilhebearin giaface-of plate 373,whichiis engaged 'by wearhplate 72; hasutwo diametrically opposed=arcuate ports 87" and 88.(Fig. 10)formed thereinupon the same: radiusasthe recesses 83 in wearp'late 72.=*When..thev

recesseszs3tand are connectedto drain by radial-grooves v 2 pump isdisehargingr-liquid under pressure recesses 83 communicate; with one ofports 87' and88. duringthe:- time that they contain-liquid at pumppressure. and they communicate with the otherof ports 87 and 88-duringthe time that theycontain liquid at-approximately'zeropres-T sureso'that, pump-pressurezprevailsin one or the other of: ports 87 and 88'dependingzupo-n the direction'in which; swash plate 57- is inclined tothe pump axis; During rota tion of swash'plate 57 and wearplate'72,the'pressure in recesses: 83 and in the high pressure ports 87 or 88-willcausei liquid atoseep therefro'mgand form a lubricating filmbetween-the matingfacesiof. plates 72 and 73.5

In orderwtot preventtpressure: in port" 87 01- 88 from causingdistortion of plate'73, two arcuaterecess'es 87 and.88t--.(Fig.: 11) ofsubstantially the same sizeandshape asi-ports 87 andt88.'arelormed inthe opposite face of plate 73 in axialsalignmeiit with ports 87 and 88,respec-- tively, and are connectedthereto'by'holes 89 (Figs. 10+ 1'3) sothat lithe pressure in eachaofmecesses 87. and 88 isthe same: pressurein.. the port 87 ,or .88 in alignment therewithrv 1 I The pressure inthe. recess 87% or-88 which is con.-

nected to the high pressure port .87 or 88 will cause liquidv plate 73radially outward from" recesses 87% and 88.

and is connectedto -dra in-by1-radialgrooves 90f." flhe a liquid seepingradially eutward frotni the recesses inner peripheral; surface ofplan-I73: 1 i

i capable of transmitting theforce v groove-1.20 are.

i 7 wApeitQexhaust-through groouescythand sauna liquid .aeepinsladially" inward from thelre'cesss can escape to exhaustthrough (oneormore axial lots 91o1fnxed litre amides pacityandioperatingiatnioderate pressures, the force I exerted lby-the pressure inithetpunaping cylinders can-be ransmitted .to theireaetionrmemherl or.cradlesv through the liquid between the matingsurfaces of the'gwearplate'and the bearing 'platef-zBut: in ..a;pump:having azlarge'volua metric.capacity. ,and operating at a .very high pressure; the fOI'CQEZlCflCdbytheliquidinthe pumping cylinders is tremendous and. is sougreat thatit itend'sto squeeze-out the lubricating film. between the-wear.platerand the bearingplate and it: causes the reactioncrnember orvcradle to.

" deflect eveniwhen the cradle is'madev as thickiand'strong as iscommercially. practicable. zThe deflectionaisi-veny small,- being onlyabout .4100 1' in .a properly-designed re-.v action memberxorv cradle,abutth; Jubricating film :is very: thin .and the deflection issuificientltocause destruc-i tion.;,of.:parts, of the evnif'ih'eliquidbetween the Wear plate and the bearing plate would otherwise be: exertedby. 'the. pressure in the pumping cylinders; a j J din-ordertoipositivelyx-maintainia lubricatingqfilm of liquid: between the matingfaces 1 of; the wear and bearing-Q- plates and? thereby preventnietal=to..-metal contact:- therebetween i with v :resultant abrasion.thereof, plate 7 3 alsoihas formed: inits hearing faceia'zplilralityofnpresi sure reeesses'flz and a plurality: of pressure recessesr93z"which are arranged radially outward,..respeetively;from ports-bland88;:1'Each recessc92 is-connectedtto poi-87 decreases to zero --at theedges of the adjacent drain pocket's96 and at the inner edge of thebearing face of plate Ihe pressure in the -fil m 'at'the edges of thepressure recesses' 92 or 93 which are connected to the high pressurepo'rt -:87 or 88 is substantially the-same as the pressure in thoserecessesand'it gradually decreasesto zero at the edges of the adjacentdrain pockets 96-andat 'theouter edge of the bearing face of plate 73.Theidrain recesses 96 thus substantially interrupt the entire front faceof the bearing and prevent'fiuid flow across the face of the bearingbetween the high pressure ports 87,..88iiand the pressure recesses 92,93. Fluid flows lacross the face oi the hearing from high pressure ports87,388 to a drain provided by the inner periphery ofithexplatex73 and tothe drain recesses 96; and fluid flows across-the .face of cthe bearingfrom the pressure recesses 92, 93 to drain provided by-the oute'rperiphery of the. bearing plate 73 and by th'e'drain recesses 96. Thedraintrecesses thus 'divide the front faces-of bearing plate 73. andthrust plate 7Zinto a first pressure area radially inward of the drainrecesses which area is subject tothe operating pressure of the fluid inholes 62 of the rotatable member, which is the same as the pumpingpressure of the machine.

. The drain groove 90 in the back face of the bearing plate and thedrain groove 85 in the back face of the wear plate define-pressure areasradially inward thereof subject to the operating pressurethat areeachefiective to .produceiforces opposed and equal to the force producedby :the operating pressure on the firstpressure area between the frontfaces of-the bearing plate and wear plate.

'Ihe drain recesses 96' also define a second pressure area radiallyoutward therefrom between the front faces by; a restricted-passages 94and each recess 9,3"is:connected V totport188 zbyxa restrictedpassage-95. v 'Passa'gess94 land 95 haitetbeensholwmasibeingxshallowgroovesiformed in the bearingvface ofrplatet73' and as being Vgshapediri cross ,setiqxritFigJM) "In the particular size;'of pump shown;-

groove'si94eand'95 areiabout -'"dee'p.

:s'The'lpressure .in the port 87101" 88 wliiichiv is the highpresspreeport vwill cause liquid tofiow therefrom. through: the passages94 and 95 intoitherrecessesnior 93 radially outward therefrom but thepressure iin the recesses will tam-lower than the pressure in'the portdue to-the resistance offered by therestricted passage'su Thetliquidtinthevhigh pressure port1 81 or SSMandjJtthe pressure recesses con nestedthereto act; as liquid bearings athroughWhich-a largepartof the lforceis transmittedflandthe balance of the force. is transmitted through the.film of liquid between *Itihas previously beeniexplainedthat thegpressureitin recesses 83' and in: the p rtwSTL'ior. 88.1 which is thehigh pressure portwill cause j 1iquid. :to eseep itherefro'mfland form.aluhricating-film: between theimating faces. of plates Ht-and :73'butzthe film is v: formed injpaltjby liquid which seepsflfroinjthe;pressure recesses 92 \or 93. which: are=con-.; nected' to the highpressure port 87 or 88. i'lnorder to lirnittheiarea'of v.thetfilminto-which pres'surefcanzextend, alpluralityxoftdrain pockets;9 6rare?formed in theibear- 1f when the pumpi'is operating the pump pressureshould increase, the force tending to move swash plate 57 toward cradle63 .wouldcorrespondingly increase and would'movec'wear plate72 closer tohearing plate 73 and-v therebyitreduce the rate at which liquid can flowthrough .the lubricating film to drain but the rate of, flow through thegrooves 94 and 95 would be reduced but little. For

' example if the thickness of the film were reduced by one half the:rate at which liquid can flow through the film to drain would be reducedto about one quarter of its previous rate but the rate at which liquidcan flow through grooves 94 or 95 would be reduced only about 2% dueto'the; depth of the grooves.

- Therefore, as soon as wear plate 72 moves closer to beating platet73and reduces the rate at which liquid can escape from the pressurerecesses 92 or 93 on the pressure sideqof the pump, the liquid flowingthrough passages 94m 95 into those grooves will. raise thepressuretherlein: and thereby. enable the liquid inithose recessesto-move: plate 72'. away from plate 73 until liquid is escaping: throughthe film from'pressure recesses 92 or 93 at-1the5same rate at whichitwas flowing into recesses dange' g'f iinetal to-metal contact betweenpla tes 72 and culdra 92 ori93lthroughgrooves 94-or95. A decrease inpump pressure :wsuiah ve no-efr'ect upon plate 72 because mere-weenbenothing to cause" it to "move. 'Conse ueasy, thelubrieating film betweenplates 72, 73 811513111 ined at a substantially uniform thiclgnessandieally'jelinaiirated regardless of variations in ib taatia iiit m: ubria i g-film; f

otatab e atera ter e ei th p .mitted and tbez ereniags: in; the ma inaac s caring; in described functions 9. thereof be formed in the adjacentfaces of swash plate 57 and cradle 63.

However, it is preferable to construct the bearing as explained aboveand to attach plates '72 and 73 or the equivalents thereof to swashplate 57 and cradle 63, respectively, to form parts thereof because themotive liquid becomes contaminated with particles of foreign matter. Itis customary to continuously pass a portion of the liquid in a hydrauliccircuit through a filter but all of the foreign matter cannot beremoved. Therefore, the mating surfaces of the thrust bearing should bevery smooth and hardened to eliminate as far as possible the danger ofthe mating surfaces being scored by the particles of foreign matter.

By providing swash plate 57 and cradle 63 with plates 72 and 73,respectively, as thus far described and making the mating faces of theplates very smooth and hard, scoring was eliminated except for a verysmall amount near the outer peripheries of the plates. Such scoringappeared to be caused by particles of foreign matter which accumulatedin recesses 92 and 93 for the reason that some of the particles offoreign matter entering the recess 92 or 93 on the pressure side of thepump were larger than the particles which could escape there frombecause the streams of liquid flowing into those recesses through thegrooves 94 'or 95 are much thicker than the film of liquid flowing outof those recesses. However, it was found that such scoring could besubstantially eliminated in the following manner:

As shown in Figs. 10, 11 and 14, a small hole 98 is extended throughplate 73 between twoadjacent recesses 92 and connected to drain groove90 by a radial slot 98 a small hole 99 is extended through plate 73between the two adjacent recesses 93 and connected to drain groove 90 bya radial slot 99, and a small pocket 100 (Figs. 14 and 15) is formed inthe face of wear plate 72 on the same radius as recesses 92 and 93.

The arrangement is such that some of the foreign particles accumulatingin recesses 92 and 93 will be picked up by pocket 100 during rotation ofplate 72. Then during the instant that pocket 100 connects the recess 92or 93 on the pressure side of the pump to the hole 98 or 99 adjacent tothat recess, the pressure in that recess will cause a shot of liquid toflow therefrom through pocket 100, the hole 98 or 99 and slot 98 or 99into drain groove 90. The shot of liquid will carry particles of foreignmatter with it into drain groove 90 and the leakage liquid flowingthrough groove 90 will carry the particles to drain.

Valve 35 (Figs. 4 and 5), bearing plate 37 (Figs. 8

and 9) thereon and the wear plate 10 (Figs. 6 and 7) on cylinder barrel7 as far as previously described are substantially the same as incertain prior pumps and would function satisfactorily under ordinaryconditions. But in order to assure maintenance of the lubricating filmof liquid between plates 10 and 37 regardless of how high a pressure thepump may create, bearing plate 37 is made very similar to bearing plate73 except that ports 39 and 40 extend completely through the plate andform continuations of the ports 39 and 40 in valve More specifically,the face of plate 37 which engages wear plate 10 has formed therein aplurality of pressure recesses 192 which are radially outward from port39 and are connected thereto by shallow radial grooves 194, a pluralityof pressure recesses 193 which are radially outward from port 40 and areconnected thereto by shallow grooves 195, and a plurality of drainpockets 196 which are arranged between port 39 and recesses 192 andbetween port 40 and recesses 193. Each drain pocket 196 is connected bya hole 197 to an annular drain groove 190 which is formed in theopposite face of plate 37 and connected to drain by radial grooves 190Pressure recesses 192 and 193, grooves 194 and 195' same Way to maintaina uniform lubricating film of liquid between plates 10 and 37.Therefore, further description is deemed unnecessary.

While it is preferable to provide bearing and wear plates between thevalve and the end of the cylinder barrel for the same reasons that it ispreferable to provide bearing and wear plates between swash plate 57 andcradle 63, the bearing and wear plates may be omitted from between thevalve and the end of the cylinder barrel and the face of the valve maybe made the same as the bearing face of plate 37 (Fig. 9) providing themotive liquid can be kept free of particles of foreign matter largeenough to score the face of the valve and/ or the end of the cylinderbarrel. Also, the restricted passages (which correspond to the grooves194 and 195 shown in Fig. 9 and through which liquid is supplied to thepressure recesses corresponding to recesses 192 and 193) may be omittedfrom the face of the valve and liquid may be supplied to the pressurerecesses in a different manner.

Figs. 17 and 18 show a valve 35* which may be substituted for valve 35and arranged substantially in contact with the end of cylinder barrel 7.Since valve 35 is substantially the same as valve 35 except that it isprovided with means for maintaining a uniform lubricating film betweenits face and the end of cylinder barrel 7, it has not been completelyillustrated and the like parts have been indicated by like referencenumerals with the exponent a added to the numerals i applied to valve 35so that only a' brief description is deemed necessary.

As shown, valve 35 is prevented from rotating by two pins 36 and it isurged against the end of cylinder barrel 7 by a plurality of hold-upmotors 45 and a plurality of hold-up motors 46 which communicate,respectively, through holes 43 and 44 with two diametrically opposedarcuate ports 39 and 40 with which each cylinder port 15 registersalternately during rota- Each pressure recess 192 communicates with theinner H end of a restricted passage shown as being a channel having aneedle valve 106 connected therein. The outer ends of the severalchannels 105 are connected to a distributing channel 107 which isconnected by a channel 108 to one of the holes 43 in communication withvalve port 39 Likewise, each pressure recess 193 communicates with theinner end of a restricted passage shown as being a channel 109 having aneedle valve 110 connected therein. The outer ends of the.

several channels 109 are connected to a distributing channel 111 whichis connected by a channel 112 to one of the holes 44 in communicationwith valve port 40 The arrangement is such that, when port 39 is thehigh pressure port, liquid can flow therefrom through holes 43 channels108 and 107-and restricted passages- 105-106 into pressure recesses 192*and maintain pres-..

sure therein. Likewise, when port 40 is the high pressure port, liquidcan flow therefrom through holes 44*, channels 112 and 111 andrestricted passages 109-110 into pressure recesses 193 and maintainpressure therein. The pressure recesses 192 and 193, the drain pockets196 and the restricted passages 1Q5-106-.and..

aiiaiada function to maintain a uniform film of liquid between valve 35and cylinder barrel 7 in the same way that pressure recesses 92 and 93,drain pockets 96, and restricted passages 94 and 95 (Fig. 10) functionto main- 1 t-ain a uniform film of liquid between plates 72 and 73 aspreviously explained. Therefore, further description or explanation isdeemed unnecessary.

'The invention herein set forth is susceptible of other modificationsand adaptations without departure from the scope of the invention whichis hereby claimed as follows:

1. In a hydrodynamic machine operable as a pump and as a motor andhaving a rotatable shaft radially rigidly supported, a first memberrigidly mounted on said shaft for rotation therewith and provided with aflat face having holes in a circular row concentric with said shaft andsuccessively supplied with liquid under the operating pressure of saidmachine, a non-rotatable second member restrained from movement axiallyof said shaft and having a flat face parallel and opposed to the flatface on the first member, and means urging said members toward eachother with a force substantially proportional to the pressure in saidholes, the improvement comprising a fiat thrust transmitting plate andan opposed flat thrust receiving bearing plate disposed between theopposed faces of said members, means securing said thrust plate innon-rotatable relation to said' rotatable member and permitting relativeaxial movement therebetween, said thrust plate having ports in oppositefaces thereof connected by axial passages in said thrust plate inalignment with said holes in said rotatable member, means securing saidbearing plate in non-rotatable relation to said second member andpermitting relative axial movement therebetween, said bearing platehaving diametrically opposed ports in front and back faces thereofconnectedby axial passages in said bearing plate and arranged so thatsaid ports in said thrust plate alternately register with said ports insaid 1 said pressure recess with one of said ports so thatrthehydrostatic forces urging said plates together are opposed by equalhydrostatic forces tending to separate them and so that the hydrostaticforces tending to separate each of said plates from the supportingmember isl'stlightly less than the hydrostatic forces between said p aes.

2. In a hydrodynamic machine operable as a pump and as a motor andhaving a rotatable shaft, a rotatable member mounted on said shaft forrotation therewith and provided with a flat face having extendingtherethrough in a circular row around the axis of said shaft a pluralityof holes which'are successively supplied with 7 liquid under theoperating pressure'of said machine as said member rotates, anon-rotatable second member restrained from movement axially of saidshaft and having a flat face adjacent and parallel to the flat face onsaid rotatable member, piston means for urging said mernbers'toward oneanother with a force substantially proportlonal to the pressure in saidholes, the improvement comprising an annular bearing plate disposedbetween sa d members, means supporting said bearing plate on said secondmember for axial movement relative thereto and in non-rotatable relationthereto, said bearing plate having a bearing face adjacent saidrotatable member with diametrically opposed arcuate ports formed thereinwith which said holes in said rotatable member alternately register assaid shaft rotates, circumferentially spaced pressure recesses formed insaid bearing face and spacedlradiallyof said ports, a limited capacitypassage connecting each said pressure recess to an adjacent said,arcuate port, drain recesses connected to exhaust and arranged betweensaid ports and said pressure recesses, a pocket in the face of saidrotatable member at the same arranged. so that said pocketsimultaneously registers with said aperture and one of said pressurerecesses for each revolution of said rotatable member.

3. In a hydrodynamic machine operable as a pump and as a motor andhaving a rotatable shaft, a first' member mounted on said shaft forrotation therewith and provided with a flat face having holes in acircular row concentric with said shaft and successively supplied withliquid under the operating pressure of said machine, a non-rotatablesecond member restrained from movement axially of said shaft and havinga flat face parallel j and opposed to the flat face on the first member,and means urging said members toward each other with a forcesubstantially proportional to the pressure in said holes, theimprovement comprising a flat thrust tr'ansmitting plate and an opposedflat thrust receiving bearing plate disposed between the opposed facesof said members, means securing said thrust plate in non-rotatablerelation to said rotatable member and permitting relative axial movementtherebetween, said thrust plate having ports in opposite faces thereofconnected by axial pas- 1 sages in said thrust plate in alignment withsaid holes in said rotatable member, means securing said bearing platein non-rotatable relation to said second member and permitting relativeaxial movement therebetween, said bearing plate having diametricallyopposed ports in front and back faces thereof connected by axialpassages in'said bearing plate and arranged so that said ports in saidthrust plate alternately register with said ports in i said bearingplate, drain recesses in the back faces of each of said plates and in afront face of one of said plates, said drain recesses connected toexhaust and spaced radially outward of said ports, pressure recessesdisposed only in a front face of one of said plates radially outward ofsaid drain recesses, and a restriction passage in a front face of one ofsaid plates connecting each said pressure recess with one of said ports,and said thrust bearing including means for cleaning the pressurerecesses comprising a drain hole in the front face of one of said platesand a pocket in the front face of the other said I plate arranged sothat said pocket simultaneously registers with both said drain hole andone of said pressure recesses for each revolution of said shaft.-

4. A machine having a non-rotatable first member re- 1 strained frommovement axially of said machine, a rotary memberhaving an annular flatface and a plurality ofholes'extending through said face in a circularrow' and normally filled with liquid, means for causing pressure to becreated in said holes, and means for urging said rotary member towardsaid first member, an annular fiat bearing face arranged upon said firstmember substantially in contact with the fiat face on saidrotary member,port means formed in said bearing face adjacent the radially innerperiphery thereof and so located that v said holes communicate therewithduring rotation of said rotary member, a plurality of relatively closelyspaced and circumferentially arranged drain recesses in said bearingface spaced radially outwardly of said arcuate ports and operabletherewith to provide a first effective pressure area-subject to saidoperating pressure,- axial ducts in said first member .each openingwithin one of said drain recesses, passage means in said first memberremote from said bearing face connecting said axial ducts to exhaust, aplurality of circumferentially spaced pressure recesses formed in saidbearing face and spaced j radially outwardly of said drain recesses andoperable therewith to provide a second effective pressure area subjectto the pressures in said pressure recesses, and a limited capacitypassage in said bearing face connecting said port means to said pressurerecesses and being the only circumferential interruption in said face insaid second effective pressure area, a thrust transmitting wear plateadapted for mounting on said rotatable member and having axial holestherethrough for alignment with the holes in said rotatable member andfor registering alternately with said ports in said bearing surface,said wear plate having a pocket in the face thereof adjacent saidbearing surface for successively registering with the pressure recesses,and an axial aperture through said first member and connected to drainremote from said bearing surface and arranged so that said pocket ismomentarily in register with both said aperture and one of said pressurerecesses for each revolution of said rotatable member.

5. In a hydrodynamic machine operable as a pump and as a motor andhaving a rotatable shaft, a first member mounted on said shaft forrotation therewith and provided with a flat face having holes in acircular row concentric with said shaft and successively supplied withliquid under the operating pressure of said machine, a non-rotatablesecond member restrained from movement axially of said shaft and havinga flat face parallel and opposed to the flat face on the first member,and means urging said members toward each other with a forcesubstantially proportional to the pressure in said holes, theimprovement comprising a flat thrust transmitting plate and an opposedflat thrust receiving bearing plate disposed between the opposed facesof said mem bers, means securing said thrust plate in non-rotatablerelation to said rotatable member and permitting relative axial movementtherebetween, said thrust plate having ports in opposite faces thereofconnected by axial passages in said thrust plate in alignment with saidholes in said rotatable member, means securing said bearing plate innon-rotatable relation to said second member and permitting relativeaxial movement therebetween, said bearing plate having diametricallyopposed ports in front and back faces thereof connected by axialpassages in said bearing plate and arranged so that said ports in saidthrust plate alternately register with said ports in said bearing plate,pressure recesses disposed only in a front face of one of said platesradially outward of said ports, and a restriction passage in a frontface of one of said plates connecting each said pressure recess with oneof said ports, drain recesses in the back faces of each of said platesand radial drain grooves disposed only in the back faces of said platesand connecting the back face of said drain recesses to exhaust,circumferentially spaced drain recesses disposed in one of the frontfaces between said ports and the pressure recesses, and axial drainpassages in said bearing plate interconnecting said drain recesses infront and back faces.

6. In a hydrodynamic machine operable as a pump and as a motor andhaving a rotatable shaft, a first member mounted on said shaft forrotation therewith and provided with a flat face having holes in acircular row concentric with said shaft and successively supplied withliquid under the operating pressure of said machine, a non-rotatablesecond member restrained from movement axially of said shaft and havinga flat face parallel and opposed to the flat face on the first member,and means urging said members toward each other with a forcesubstantially proportional to the pressure in said holes, theimprovement comprising a flat thrust receiving bearing plate disposedbetween the opposed faces of said members, means securing said bearingplate in nonrotatable relation to said second member and permittingrelative axial movement therebetween, said bearing plate havingdiametrically opposed arcuate ports in front and back faces thereofinterconnected by axial passages in said bearing plate and said portsarranged so that said holes in said first member alternately communicatetherewith, pressure recesses disposed only in a front face of saidbearing plate radially outward of said ports, limited capacity passageseach connecting one of said pressure recesses with an adjacent one ofsaid ports for restricted flow therebetween, circumferentially extendingdrain recesses concentrically arranged in the face of the bearing platebetween said pressure recesses and said ports, an annular drain recessin the back face of the bearing plate, axial drain passages through thebearing plate interconnecting the drain recesses in the front face withthe drain recess in the back face, and radial drain grooves leading toexhaust disposed only in 'the back face of the bearing plate andconnected to said annular drain recess.

References Cited in the file of this patent UNITED STATES PATENTS Re.20,026 Thoma June 30, 1936 2,155,455 Thoma Apr. 25, 1939 2,250,512Vickers July 29, 1941 2,298,850 Vickers Oct. 13, 1942 2,337,821 HuberDec, 28, 1943 2,463,299 Nixon Mar. 1, 1949 2,546,583 Born L. Mar. 27,1951 2,646,754 Overbeke July 28, 1953 2,699,123 Bonnette et a1. Jan. 16,1955 2,721,519 Henrichsen Oct. 25, 1955 2,737,899 Bonnette et a1 Mar.13, 1956 2,757,612 Shaw Aug. 7, 1956 2,847,938 Gondek Aug. 18, 1958FOREIGN PATENTS 220,417 Great Britain Aug. 21, 1924 604,168 GreatBritain June 29, 1948

